Devices for detecting information which is contained in a phosphor layer are used in the field of computer radiography (CR), particularly for medical purposes. X-ray images are recorded in a phosphor layer, X-ray radiation which passes through an object, for instance a patient, being stored as a latent image in the phosphor layer. To read out the latent image, the phosphor layer is irradiated with stimulation light and thus stimulated to emit emission light, which corresponds to the latent image which is stored in the phosphor layer. The emission light is detected by an optical detector and converted into electrical signals, which are processed further as required, and presented on a monitor or an appropriate output device, e.g., a printer.
From the prior art, devices in which the stimulation light from a light source is focused on a linear area of the phosphor layer are known. For focusing, in general cylinder lenses are used. However, in cases in which the light source is formed by multiple individual radiation sources, there is the problem that the sharpness of the stimulation line on which the stimulation line bundles emitted from the individual radiation sources are focused, varies along the stimulation line depending on the distance of the individual radiation sources. For instance, an equidistant arrangement of the individual radiation sources results in a periodic variation of the sharpness of the stimulation line. The breadth of the stimulation line on the phosphor layer also varies with the sharpness of the focusing of the stimulation light. This affects the image quality, since for this the sharpest possible delimitation of the stimulation line is required.